Development of Break-Away Sign Supports and Slotted Steel Plate Mechanical Fuses

摘要

The overall study findings are summarized and test data are presented on a modification of the fuse plate design for the original Texas break-away sign support concept. The original frangible cast-iron fuse plate was replaced with a slotted steel plate after premature in-service fractures were observed in several cases due to casting imperfections and bolting stresses. Details of bolt size and plate thickness were investigated by laboratory tests. Five specimens on each of three typical post signs were investigated. Tests simulated a wind load failure of a new sign support and a wind load failure of a support which had been reconditioned following a collision. Tests were also run to determine the effect of weathering on fuse plate response. The report concluded that reerection following a collision does not diminish a sign support wind load capacity and that weathering has no detrimental effect on a fuse plate. (BPR abstract)